This invention relates to self-contained missile canisters, and more particularly to such canisters which include ducting for reversing the direction of exhaust gases and venting in the forward direction.
The use of rocket-powered missiles for warfare is at least two hundred years old. As missiles have become more sophisticated, the need for protection of the missiles against weather and damage has led to the use of missile canisters, which can be transported and stored with little danger of damage to the missile or missiles contained therein, and from which the missile may be launched. Some early forms of such canisters were not fully weathertight, and U.S. Pat. No. 5,153,367, issued Oct. 6, 1992 in the name of Markquart et al. describes a cocoon for protecting a rectangular missile canister having an open launch or exhaust end from the environment. The Markquart et al. cocoon can be mounted on a structure to tilt it to the angle desired for launch. An exhaust system is associated with the cocoon for deflecting the exhaust gases by angles greater or less than 90xc2x0. As noted in the Markquart et al. patent, the cocoon provides for a simpler structure than that required for vertical launch from within a ship, because vertical launch requires that the exhaust gases be routed from the interior of the launch ship to the exterior. It should be noted that more recent canisterized missiles are more completely sealed against the environment than early missiles, and include frangible or other end seals which rupture or open when the missile is fired, to thereby allow the missile to exit the front end of the canister, and exhaust gases to exit the rear of the canister. Such an arrangement protects the missile until the last possible moment at which the missile is launched from the container.
U.S. Pat. No. 5,847,307, issued Dec. 8, 1998 in the name of Kennedy et al. describes a ship-borne vertical launch arrangement for canisterized missiles. The structure includes a framework defining elongated rectangular receptacles, each of which is dimensioned to accommodate one missile canister. At the bottom end of the multiple-receptacle structure, a plenum or manifold interconnects all of the receptacles. When the structure is loaded with missile canisters, at least one of the receptacles is left without a missile canister, and firing of any of the missiles causes the exhaust from that missile to be routed through the open receptacle to the top side or exterior of the ship. Firing of other missiles after the first allows the exhaust gas to be further routed through a now-empty or open canister as well as through the open receptacle. Erosion of the plenum is reduced by water injection.
U.S. Pat. No. 5,837,919, issued Dec. 8, 1998 in the name of Yagla et al. describes a portable launcher for a missile. The portable launcher includes an inner missile holding structure concentric with a cylindrical outer structure, with an annulus or annular interstice lying between the inner and outer structures. A plenum is defined at the rear or missile-exhaust end of the structure, which routes the exhaust gases from the inner missile holding structure through the annular interstice to the front of the portable launcher. The inner and outer structures are held in fixed relation by supports extending therebetween. In some embodiments, the supports are arranged to provide clearance for projecting portions of the missile, such as for example aerodynamic fins.
Improved missile canister arrangements are desired.
A self-contained missile canister according to an aspect of the invention includes a missile which is elongated about an axis. The missile has an axially projected body shape which includes a circular portion and projections extending beyond the radius of the circular portions at plural circumaxial positions. In this context, a circumaxial position is an angular position or range measured from a reference angle in a circumferential manner about a point along the axis. The self-contained missile canister includes an elongated canister storage and launch duct defining a missile exit end and a rear or breech end. The storage and launch duct has a circular cross-sectional shape and a cross-sectional diameter which is larger than the largest cross-sectional diameter of the missile at the projections, whereby a plurality of elongated regions lie between the missile and the interior of the storage and launch duct over circumaxial regions other than the plural circumaxial positions of the missile. A plenum is affixed to the breech end of the canister storage and launch duct, for deflecting exhaust gases generated by the missile within the storage and launch duct during launch. A plurality of elongated, tubular exhaust ducts lie adjacent the interior of the canister storage and launch duct within the circumaxial regions other than the plural circumaxial positions of the missile. Each of the exhaust ducts has a circular cross-section, and each of the exhaust ducts of set 36 is coupled to the plenum for receiving the exhaust gases from the plenum. In addition, each of the exhaust ducts of set 36 extends from the plenum to at least near the missile exit end of the storage and exhaust duct, for routing the exhaust gases deflected by the plenum to the missile exit end of the storage and launch duct. In a particular self-contained missile canister according to the invention, the axially projected body shape is roughly square, thereby providing four circumaxial regions other than the plural circumaxial positions of the missile.
In a particularly advantageous version of the self-contained missile canister according to the invention, a plurality of elongated support beams are provided, each extending along at least a portion of the length of the storage and launch duct within one of the circumaxial regions other than the plural circumaxial positions of the missile. In a desirable avatar of the invention, each of the elongated support beams supports at least one of the exhaust ducts, and preferably two exhaust ducts. The support beams are preferably I-beams defining two flanges and a web, with one of the flanges affixed to the interior wall of the storage and launch duct. When an I-beam is used to support one or more exhaust ducts, the web of the I-beam is preferably concave on the side facing the exhaust duct being supported, so as to tend to provide an area support. In one embodiment, most of the exhaust ducts are paired for support by I-beams. To save weight, the material of the exhaust ducts may be reinforced composite material. An ablative lining may be employed with the exhaust ducts to prevent burn-through of the walls of the duct.
Taking another view of the invention, a self-contained missile canister includes a missile having a body which has at least some cross-sections which are generally circular, and which may also include cross-sections which exhibit projecting portions extending beyond the largest of the generally circular cross-sections, whereby a projection of the shape of the missile body, with its projecting portions, onto a plane orthogonal to an axis of the missile defines an exterior shape. An elongated canister storage and launch duct defines a longitudinal axis, a missile exit end, and a rear or breech end. The storage and launch duct has a circular internal cross-sectional shape at least near the missile exit end which clears the exterior shape of the missile, whereby space is available between the exterior of the missile and the interior of the storage and launch duct at locations removed from the projecting portions. A plenum is affixed to the rear or breech end of the storage and launch duct, for deflecting exhaust gases generated by the missile within the storage and launch duct. A plurality of elongated, tubular exhaust ducts lie at least partially within the space with their axes parallel to the longitudinal axis of the storage and launch canister. Each of the exhaust ducts is coupled to the plenum, and extends to at least near the missile exit end of the storage and exhaust duct, for routing the exhaust gases deflected by the plenum to the missile exit end of the storage and launch duct. The projecting portions of the missile body may include aerodynamic fins, which may be disposed by equal angular increments about an axis of the missile. Ablative material may be used within the exhaust ducts of set or the entire exhaust duct may be made from ablative material. In this context, reinforced composite material may be viewed as ablative material.